Benefits of Lowering Cholesterol Levels in Older Patients

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The summary below is from the full report titled "Benefits of Pravastatin on Cardiovascular Events and Mortality in Older Patients with Coronary Heart Disease Are Equal to or Exceed Those Seen in Younger Patients: Results from the LIPID Trial." It is in the 15 May 2001 issue of Annals of Internal Medicine (volume 134, pages 931-940). The authors are D Hunt, P Young, J Simes, W Hague, S Mann, D Owensby, G Lane, and A Tonkin, for the LIPID Investigators.

What is the problem and what is known about it so far?

Coronary heart disease is a major cause of death in middle-aged and older adults. Several factors, including a high blood cholesterol level, can increase a person's risk for this type of heart disease. Various diet and drug treatments can help lower cholesterol and reduce the risk for heart disease. For example, drug treatments that lower blood cholesterol levels can prevent heart attacks and deaths from coronary heart disease in middle-aged adults. How well these drug treatments work in older adults has not been clear, however.

Why did the researchers do this particular study?

To see whether pravastatin, a drug that lowers cholesterol levels, is more or less effective in preventing heart disease in people 65 years of age or older compared with people 31 to 64 years of age.

Who was studied?

The study included 3514 men and women 65 to 75 years of age and 5500 men and women 31 to 64 years of age. All had had a heart attack or severe chest pain from heart disease. Some participants had cholesterol levels that were in the normal range, but the average cholesterol level among participants was high.

How was the study done?

The researchers randomly assigned participants to receive either 40 mg of pravastatin daily or placebo pills. The placebo looked like pravastatin but did not contain any active ingredients. Participants were then followed for 6 years.

What did the researchers find?

Compared with placebo, pravastatin lowered cholesterol levels and prevented bad outcomes in both older and younger participants. For every 1000 older patients treated during the 6-year study, pravastatin prevented 45 deaths and 133 major coronary events, including heart attacks, strokes, severe chest pain episodes, and heart surgeries. For every 1000 younger patients, pravastatin prevented 22 deaths and 107 major coronary events over 6 years. Both older and younger participants were able to take pravastatin without frequent or severe side effects.

What were the limitations of the study?

This study was originally designed to see whether pravastatin would help people 31 to 75 years of age who already had heart disease. The decision to see whether the benefits of pravastatin were similar in older and younger participants was made after the study was completed; the findings may be less reliable because the study was not primarily designed to answer this question.

What are the implications of the study?

Pravastatin prevents deaths and other major heart- and circulation-related problems in both older and younger people with known heart disease and average or high cholesterol levels. The potential benefits of treatment over 6 years are higher for older than for younger people, mainly because older people have greater risks for heart and circulation problems to begin with.